The present invention generally relates to signal trace routing designs, and more particularly to a method for matching the lengths of signal traces in view of signal propagation delays in a circuit board layout environment.
Software programs for routing or laying out signal traces on circuit boards, such a printed circuit board (PCB) and a backplane or motherboard are well known in the art. Computer aided design (CAD) software is one such program. These programs, however, do not have the capability for accurately matching the lengths of signal traces when there are signal propagation delays. These delays are typically caused by interface connectors on the PCB and the different material used for the substrates on which the signal traces are formed, for example.
Presently, even when the lengths of the traces are matched, each time an adjustment is made to one trace length, the lengths of the other trace or traces being matched must also be adjusted, thereby requiring multiple iterations of manual adjustments. Also, information regarding propagation delays cannot be back annotated to the existing software programs, which makes matching the trace lengths difficult.
Accordingly, it is a primary objective of the present invention to provide an improved method for matching the trace lengths of at least two signal traces on a circuit board.
Another object of the present invention is to provide an improved method for matching signal traces that are connected between at least two circuit boards.
Still another object of the present invention is to provide such an improved method for matching signal trace lengths, which does not require multiple iterations of adjustments.
Yet another object of the present invention is to provide such an improved method for matching the trace lengths, which can be imported into a known software program.
An additional object of the present invention is to provide such an improved method for matching signal trace lengths in which the traces are divided into segments.
More particular object of the present invention is to provide such an improved method for matching the signal traces in which the longest trace length is calculated and the lengths of the shorter signal traces are adjusted by the difference between the longest trace and the shorter traces.